1,2,4-Oxadiazole derivatives and herbicide composition containing same

3-[3-(3,3-dimethylureido)-phenyl]-5-trifluoromethyl-1,2,4-oxadiazole

Variant A

41.35 g (0.22 mol) of 3-(N,N-dimethylureido)-benzonitrile and 16.68 g (0.24 mol) of hydroxylammonium-chloride were suspended in 300 ml methanol. While stirring 9.60 g (0.24 mol) of sodium hydroxide were added and the mixture was subjected to boiling for 6 hours under reflux.

The reaction mixture was then filtered while hot and the filtrate was concentrated in a vacuum. The residue was subjected to repeated stirring with ether and was then dried at room temperature in a vacuum. The yield was 5-(N,N-dimethylureido)-benzamidoxime in an amount of 41.5 g=84.9% of the theoretical amount. The melting point of the compound was 186° C. (decomposition).

39.5 g (0.18 mol) of the last-obtained 3-(N,N-dimethylureido)-benzamidoxime were then suspended in 400 ml of tetrahydrofuran and were reacted during a period of 20 minutes while stirring with 25.2 ml (0.18 mol) of trifluoroacetanhydride. The reaction temperature during that step rose from 25° to about 38° C. Undissolved residue was filtered off, the filtrate was subjected to concentration by evaporation and the residue was recrystallized from acetic acid ester/hexane.

The yield was 3-[3-(3,3-dimethylureido)-phenyl]-5-trifluoromethyl-1,2,4-oxadiazole in an amount of 29.7 g=55% of the theoretical value. The melting point of the compound was 155° to 158° C.

Variant B

55.8 g (0.31 mol) of 3-nitrobenzamidoxime were dissolved in 900 ml of tetrahydrofuran and were reacted within a period of 1 hour by dropwise addition under stirring of 43.1 ml (0.31 mol) trifluoroacetic anhydride. During this operation the temperature rose by 10° C. After 3 hours the formation of the 1,2,4-oxadiazole was complete. The mass was then poured into 2 liter of ice water. The reaction product thereafter was extracted with acetic ester. The acetic ester phase was washed with water, dried on magnesium sulfate and stirred by revolving it. There were obtained 3-(3-nitrophenyl)-5-trifluoromethyl-1,2,4-oxadiazole in an amount of 52.8 g=65.7% of the theoretical value. The melting point of the compound was 77°-78° C.

49.6 g (0.19 mol) of the just-obtained 3-(3-nitrophenyl)-5-trifluoromethyl-1,2,4-oxadiazole were dissolved in 700 ml ethanol and were reacted with 80 ml H 2 O and 16.9 g (0.31 mol) of ammoniumchloride. 93.1 g (1.4 mol) of zinc powder were then added in batches while cooling by ice within a period of 30 minutes. The temperature during that operation should not exceed 30° C. After about 1 hour the reaction was complete.

The product was then filtered off the zinc and the alcohol was incorporated by revolving the mass. The residual oil was then taken up with acetic ester and the mass was washed twice with 300 ml water. The acetic ester phase was dried on magnesium sulfate, filtered and stirred by revolving it. The yield was 3-(3-aminophenyl)-5-trifluoromethyl-1,2,4-oxadiazole in an amount of 33 g=75.8 of the theoretical value. This compound was in the form of a yellow oil.

29.4 g (0.13 mol) of 3-(3-aminophenyl)-5-trifluoromethyl-1,2,4-oxadiazole were then dissolved in 75 ml pyridine and were reacted dropwise with 13.8 ml (0.15 mol) of dimethylcarbamoylchloride. The reaction temperature during this operation rose to a maximum of 40° C. At this temperature the mass was subjected to further stirring for 2 hours. Subsequently, the mass was poured onto 1 liter of water and the product was extracted with acetic ester. The organic phase was washed twice with 300 ml water, dried on magnesium sulfate and stirred with a rotating movement.

The crude product was recrystallized from acetic ester/hexane. The yield was 24.3 g=45% of the theoretical value of 3-[3-(3,3-dimethylureido)-phenyl]-5-trifluoromethyl-1,2,4-oxadiazole; melting point 155° to 158° C.

3-butyl-5-[3-(3,3-dimethylureido)-phenyl]-1,2,4-oxadiazole

11.6 g (0.1 mol) of valeric acid amidoxime were dissolved in 300 ml of tetrahydrofuran and reacted with 13.6 ml (0.1 mol) of triethylamine. 17.4 g (0.1 mol) of 3-nitrobenzoylchloride were then added dropwise while stirring. The reaction temperature during this step rose to a maximum of 35° C. Stirring was then continued for 3 hours. The mass was then separated from the triethylaminohydrochloride by suction and the filtrate was subjected to stirring by a rotating movement. The oily residue was taken up in 300 ml toluene, reacted with 300 mg p-toluenesulfonic acid and heated under reflux for 8 hours with a water separator. After cooling the reaction mixture was filtered and the filtrate was subjected to rotary stirring. The yield was 3-butyl-5-(3-nitrophenyl)-1,2,4-oxadiazole in an amount of 19.7 g=96% of the theoretical value; n D 20=1.5520.

12.3 g of (0.05 mol) of 3-butyl-5-(3-nitrophenyl)-1,2,4-oxadiazole were dissolved in a mixture of 250 ml ethanol and 25 ml water and were reacted with 4.5 g (0.085 mol) of ammonium chloride. 25.0 g (0.38 mol) of zinc powder were then added batchwise while stirring. The reaction temperature during that step rose to between 35° and 40° C. Stirring was continued for an hour. Subsequently, the mass was separated from the zinc by suction and the filtrate was subjected to rotary stirring. The residue was taken up with 200 ml of ether. The solution was washed twice with 50 ml of water, dried on magnesium sulfate, and filtered. The filtrate was then subjected to rotary stirring. The yield was 5-(3-aminophenyl)-3-butyl-1,2,4-oxadiazole in an amount of 8.2 g=75.9% of the theoretical value; n D 20=1.5735.

8.0 g (0.037 mol) of 5-(3-aminophenyl)-3-butyl-1,2,4-oxadiazole were dissolved in 15 ml pyridine and were reacted with 3.4 ml (0.037 mol) of dimethylcarbamoylchloride. The reaction was complete after stirring for 8 hours at room temperature. The mass was then reacted with about 100 ml ice water resulting in precipitation of the reaction product. The reaction produce was removed by suction, subjected to drying at 50° C. in a vacuum and recrystallized from diisopropylether. There were obtained 8.3 g=77.5% of the theoretical value of 3-butyl-5-[3-(3,3-dimethylureido)-phenyl]-1,2,4-oxadiazole; m.p. 108° to 110° C.

3-[3-(3-methylureido)-phenyl]-5-trifluoromethyl-1,2,4-oxadiazole

23 g (0.1 mol) of 3-(3-aminophenyl)-5-trifluoromethyl-1,2,4-oxadiazole as obtained as intermediate product in variant B of Example 1 were dissolved in 60 ml diethylether and were reacted after addition of a catalytic amount of triethylamine with 6.5 ml (0.1 mol) of methylisocyanate upon stirring and water cooling. The reaction temperature in this step rose to a maximum of 30° C. The reaction was complete after 1 hour. The solid reaction product was removed by suction, was recrystallized from acetonitrile and dried in a vacuum. There were obtained 19 g=66.5% of the theoretical value of 3-[3-(3-methylureido)-phenyl]-5-trifluoromethyl-1,2,4-oxadiazole; m.p. 141° to 143° C.

The following compounds were obtained in a manner analogous to the compounds described in the preceding examples.

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Physical

Compound Constants

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3-(3-n-propoxycarbonylamino)-phenyl-

m.p.: 80°-82° C.

5-trifluoromethyl-1,2,4-oxadiazole

3-[3-(3,3-dimethylureido)-phenyl]-5-

trifluoromethyl-1,2,4-oxadiazole

m.p.: 163°-165° C.

(decomposition)

3-[3-(3-isopropylureido)-phenyl]-5-

trifluoromethyl-1,2,4-oxadiazole

m.p.: 171°-173° C.

3-[3-(3-ethylureido)-phenyl]-5-methyl-

1,2,4-oxadiazole m.p.: 141°-142° C.

3-[3-(3-isopropylureido)-phenyl)-5-

methyl-1,2,4-oxadiazole m.p.: 183°-185° C.

5-ethyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

m.p.: 154°-156° C.

5-cyclopropyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

m.p.: 148°-150° C.

5-tert.-butyl-3-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

m.p.: 117°-120° C.

3-[3-(3,3-dimethylureido)-phenyl]-5-

isopropyl-1,2,4-oxadiazole

m.p.: 86°-90° C.

3-[3-(3,3-dimethylureido)-phenyl]-5-

propyl-1,2,4-oxadiazole m.p.: 100°-104° C.

3-[3-(3,3-dimethylureido)-phenyl] -5-

(2-methylpropyl)-1,2,4-oxadiazole

m.p.: 65°-70° C.

-3-[3-(3,3-dimethylureido)-phenyl]-5-

trichloromethyl-1,2,4-oxadiazole

m.p.: 130°-134° C.

5-cyclohexyl-3-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

m.p.: 143°-146° C.

5-benzyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxydiazole

m.p.: 153°-156° C.

3-[3-(3,3-dimethylureido)-phenyl]-5-

(3-methylphenyl)-1,2,4-oxadiazole

m.p.: 174°-177° C.

3-[3-(3,3-dimethylureido)-phenyl]-5-

(4-methylphenyl)-1,2,4-oxadiazole

m.p.: 203°-207° C.

5-(dichloromethyl)-3-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

m.p.: 110°-114° C.

5-(4-tert.-butylphenyl)-3-[3-(3,3-di-

methylureido)-phenyl]-1,2,4-oxadiazole

m.p.: 156°-160° C.

5-(4-chlorophenyl)-3-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

m.p.: 189°-190° C.

5-tert.-butyl-3[(3-methoxycarbonyl-

amino)-phenyl]-1,2,4-oxadiazole

m.p.: 86°-89° C.

3-[3-(cyclopropylcarbonylamino)-phenyl]

5-tert.butyl-1,2,4-oxadiazole

m.p.: 75°-80° C.

3-[3-(butyrylamino)-phenyl]-5-tert.-

butyl-1,2,4-oxadiazole m.p.: 85°-90° C.

3-[30(3,3-diethylureido)-phenyl]-5-

tert.-butyl-1,2,4-oxadiazole

m.p.: 132°-135° C.

3-[3-(3,3-dimethylureido)-phenyl]-5-

phenyl-1,2,4-oxadiazole m.p.: 159°-163° C.

3-tert.-butyl-5-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

m.p.: 121°-123° C.

3-tert.butyl-5-[3-(3-methylureido)-

phenyl]-1,2,4-oxadiazole

m.p.: 170°-174° C.

5-chloromethyl-3-(3-cyclopropyl-car-

bonylaminophenyl)-1,2,4-oxadiazole

m.p.: 134°-137° C.

3-(3-cyclopropylcarbonylaminophenyl)-

5-methyl-1,2,4-oxadiazole

m.p.: 171°-174° C.

3-(3-cyclopropylcarbonylaminophenyl)-

5-trifluoromethyl-1,2,4-oxadiazole

m.p.: 138°-142° C.

3-[3-(3,3-dimethylureido)-phenyl]-

5-phenyl-1,2,4-oxadiazole

m.p.: 159°- 163° C.

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The compounds of the invention had a good solubility in acetic acid ethylester, acetone and alcohol. However, their solubility was only moderate in benzene and they were virtually insoluble in saturated hydrocarbons and water.

The compounds listed in the Table 1 below were sprayed onto mustard and tomatoes as test plants in a preemergence and postemergence application in amounts of 5 kg of active agent per about 2.5 acres emulsified in 500 liters of water per 2.5 acres.

The results of the treatment were evaluated after 3 weeks on a scale from 0=no effect, to 4=total destruction of the plants. As appears from the table normally a total destruction of the test plants was accomplished.

This test is a laboratory experiment in which mustard and tomatoes as test plants represent or simulate an undesired growth. These tests therefore are made to permit an evaluation of suitable control activities.

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Postemergence

application

Compounds mustard tomato

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3-[3-(3-methylureido)-phenyl]-5-

trifluoromethyl-1,2,4-oxadiazole

4 4

3-(3-n-propoxycarbonylamino)-phenyl-

5-trifluoromethyl-1,2,4-oxadiazole

4 4

3-[3-(3,3-dimethylureido)-phenyl]-5-

trifluoromethyl-1,2,4-oxadiazole

4 4

3-[3-(3,3-dimethylureidophenyl)]-5-

methyl-1,2,4-oxadiazole 4 4

5-ethyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

4 4

5-cyclopropyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

4 4

5-tert.-butyl-3-[3-(3,3-dimethylureido)-

phenyl]1,2,4-oxadiazole 4 4

3-[3-(3,3-dimethylureido)-phenyl]-5-

isopropyl-1,2,4-oxadiazole

4 4

3-[3-(3,3-dimethylureido)-phenyl]-5-

propyl-1,2,4-oxadiazole 4 4

3-[3-(3,3-dimethylureido)-phenyl]-5-

(2-methylpropyl)-1,2,4-oxadiazole

4 4

5-cyclohexyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

4 4

5-benzyl-3-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

4 4

3-[3-(3,3-dimethylureido)-phenyl]-

5-(3-methylphenyl)-1,2,4-oxadiazole

4 4

5-(dichloromethyl)-3-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

4 4

5-(tert.-butylphenyl)-3-[3-(3,3-

dimethylureido)-phenyl]-1,2,4-

oxadiazole 4 4

5-(4-chlorophenyl)-3-[3-(3,3-di-

methylureido)-phenyl]-1,2,4-oxa-

diazole 4 4

5-tert.-butyl-3-[3-(methoxycarbonyl-

amino)-phenyl]-1,2,4-oxadiazole

4 4

3-[3-(cyclopropylcarbonylamino)-

phenyl]-5-tert.-butyl-1,2,4-

oxadiazole 4 4

3-[3-(butyrylamino)-phenyl]-5-tert.-

butyl-1,2,4-oxadiazole 4 4

3-(n-butyl)-5-[3-(3,3-dimethylureido)-

phenyl]-1,2,4-oxadiazole

4 4

3-[3-(3,3-diethylureido)-phenyl]-5-

tert.-butyl-1,2,4-oxadiazole

4 4

3-[3-(3,3-dimethylureido)-phenyl]-

5-phenyl-1,2,4-oxadiazole

4 4

3-tert.-butyl-5-[3-(3,3-dimethyl-

ureido)-phenyl]-1,2,4-oxadiazole

4 4

3-tert.-butyl-5-[3-(3-methyl-

ureido)-phenyl]-1,2,4-oxadiazole

4 4

5-chloromethyl-3-(3-cyclopropyl-

carbonylaminophenyl)-1,2,4-oxadiazole

4 --

3-(3-cyclopropylcarbonylaminophenyl)-

5-methyl-1,2,4-oxadiazole

4 4

3-(3-cyclopropylcarbonylaminophenyl)-

5-trifluoromethyl-1,2,4-oxadiazole

4 --

3-[3-(3,3-dimethylureido)-phenyl]-

5-phenyl-1,2,4-oxadiazole

4 4

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The plants listed in the Table 2 below were treated in a hothouse prior to emergence with the agents also listed in the table. The compounds were applied as aqueous solutions in amounts of 1 kg of active agent per about 2.5 acres in 500 liter water for the same area and were spread uniformly onto the soil.

The results appearing from the table show that the compounds of the invention as distinguished from the compound of the British Pat. No. 913,383 which is used as comparison compound, show a higher activity at the same selectivity. For the evaluation of the test results a scale was used in which 0 was equal to total destruction of the plant and 10 was equal to no damage to the plant.

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Chry-

San-

Lam-

Cent-

Amar-

the-

Ipo-

Poly-

Alo-

soy-

pota-

ium aurea

anthus

mum moea

gonum

pecurus

Compounds of the Invention

wheat

maize

rice

beans

toes

a. C. r. s. p. l. m.

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3-[3-(3,3-dimethylureido)-

phenyl]-5-trifluoromethyl-

1,2,4-oxadiazole

10 10 10 10 10 0 0 0 0 0 0 0

3-[3-(3,3-dimethylureido-

phenyl)]-5-tert.-butyl-

1,2,4-oxadiazole

10 10 10 10 10 0 0 0 0 0 0 0

Comparison Compound

(British Patent 913,383)

N'-4-(4-chlorophenoxy)-

phenyl-N,N-dimethyl urea

10 10 10 10 10 1 3 3 4 6 3 8

Untreated 10 10 10 10 10 10 10 10 10 10 10 10

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The plants listed below in Table 3 were treated in a hothouse after emergence with the compounds of the invention in amounts of 1 kg of active agent per 2.5 acres. The compounds for this purpose were sprayed onto the plants in a uniform manner.

The results of this test in the evaluation after 3 weeks likewise show a high selectivity to the tested agricultural plants together with a high activity against weeds. The evaluation of the treatment was effected on a scale in which 0 was equal to total destruction, and 10 was equal to no damage to the plant.

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Da-

Ipo-

Se Digit-

Euph-

pea- Kochia

Escholtzia

tura

moea

taria

aria

orbia

Compounds of the Invention

nuts

rice

sp. sp. sp.

sp.

sp.

sp. sp.

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3-[3-(3,3-dimethylureido)-

phenyl]-5-trifluoromethyl-

1,2,4-oxadiazole

10 10 0 0 0 0 0 0 0

3-[3-(3,3-dimethylureido-

phenyl)]-5-tert.butyl-

1,2,4-oxadiazole

10 10 0 0 0 0 0 0 0

Untreated 10 10 10 10 10 10 10 10 10

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Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.